The transportation of goods by truck, rig and trailers is a key industry in modern society. However, it is not unusual for the axle or axles on a trailer to get out of alignment. This may occur on account of the trailer wheels striking an abutment or from the trailer body becoming bent or from some other reason. Such out of alignment conditions of the axle or axles of a trailer will lead to rapid tire wear which results in a big expense for the trailer owner or at the same time, creating a hazardous condition which may cause jackknifing and makes it difficult to control the trailer easily on the road.
Furthermore, there is a lateral drag on the back end of the trailer which in turn causes tire wear on the trailer tractors and difficulties in handling the tractor. Accordingly it is not unusual for tractors to run at excessive torquing. All of these conditions create unnecessary fuel consumption, deterioration in the life of the tractor, tires wearing prematurely, strain on engine parts and increased engine down time.
Accordingly, there is a need for devices to measure the distance between a plurality of axles on a trailer. There is also a need for an improved method for aligning the axles on a vehicle.
There have been a number of arrangements heretofore which have been designed for aligning axles for trailers. For example some operators use a tape measure to measure the distance between the centre line of the king pin and the ends of each axle. This tends to be inaccurate as the tape tends to sag. Furthermore obstacles under the trailer are encountered by the sagging tape making it difficult to obtain an accurate reading.
Other arrangements are shown in U.S. Pat. No. 2,479,723 which relates to a method and means for aligning the rear axles of trailers. Furthermore, U.S. Pat. No. 2,590,722 relates to a device for aligning the wheels and axles of a vehicle in relation to the line of draft of the vehicle.
Moreover, U.S. Pat. No. 2,632,256 relates to an axle alignment device while U.S. Pat. No. 2,845,718 relates to gauging and aligning devices for vehicle axles.
Another arrangement for aligning of axles of trailers is shown in U.S. Pat. Nos. 2,877,560, 3,088,214 and 3,137,076.
U.S. Pat. No. 3,162,950 also relates to a method and means for a trailer axle alignment while U.S. Pat. No. 3,279,084 relates to a trailer axle misalignment and wheel runout indicator and method.
Other arrangements for axle aligning are discussed in U.S. Pat. Nos. 3,325,905, 3,566,476, 3,686,770, 3,962,796, and 4,055,899.
U.S. Pat. No. 4,347,668 relates to apparatus for aligning the axles of trailers having an instrument case connected by an elongated spring-loaded cable to the trailer king pin and connected by a pair of cables to clips releaseably fastened on space location to the trailer axle.
Furthermore, U.S. Pat. No. 4,413,420 relates to a vehicle geometry checking apparatus or U.S. Pat. No. 4,569,140 relates to a thrust line wheel alignment apparatus and method.
Moreover U.S. Pat. No. 4,800,651 relates to an apparatus and method for aligning axles with respect to the frame of the vehicle and for determining wheel camber thereof.
Furthermore, U.S. Pat. No. 4,942,667 illustrates a portable apparatus for aligning the axles of a tractor, a trailer, or other vehicle for detecting bins, bows, twists and other irregularities in vehicle frames which a light source has used to provide a reference plane from which measurements can be taken. Such arrangement illustrates a complicated and expensive means for aligning axles on a trailer.
Further, U.S. Pat. No. 5,125,164 relates to a portable axle and frame alignment tool while U.S. Pat. No. 5,157,838 shows a vehicle axle alignment instrument and method.
A tandem axle alignment device is illustrated in U.S. Pat. No. 5,367,778 while U.S. Pat. No. 6,021,576 relates to a trailer trammel. Finally, U.S. Pat. No. 6,233,837 relates to an axle alignment system which includes a transmitter, reflector and an indicator area.
These and other devices and methods described are relatively complicated and expensive means for aligning the axles on a trailer.
It is an object of this invention to provide an improved device and method for aligning at least one axle of a wheel relative to the king pin of a trailer.
It is an aspect of this invention to provide a device for aligning with a king pin on a trailer which comprises a first bar having a first coupler at one end thereof, a second bar having a second coupler at one end thereof, whereby the first and second couplers are adapted for attachment to the king pin, each bar having a projection therefrom for aligning said rods on said trailer when said couplers are attached to such king pin.
It is another aspect of this invention to provide a tool for measuring the distance between an axle on each side of a vehicle comprising two telescoping members, a means for adjustably securing said telescoping members together, each said telescoping members having selectively displaceable axle contacting rods projecting outwardly therefrom, for measuring the distance between said axles on one side of said vehicle, and for comparing the distance between said axles on said other side of said vehicle, said axle contacting rods including rounded ends for contacting said axle.
It is another aspect of this invention to provide a method of aligning a plurality of axles on a trailer having a king pin comprising:                placing a bar each having a first and second coupler at one end thereof and a second end thereof under said trailer;        assembling said couplers around said king pin;        aligning said bars relative to said trailers so as to extend said other ends of said bars on either side of said trailer;        attaching an axle extender to each said sides of first said axle;        connecting a plurality of measured rods together on each side of said trailer so as to close the distance of said other end of said first and second bars and said axle extenders;        measuring said distance on each side of said trailer;        adjusting said first axle to substantially equalize said distances.        
These and other objects and features of this invention shall now be described in relation to the following drawings: